Module for a heat pump

ABSTRACT

The invention relates to a module for a heat pump, comprising an adsorption-desorption region, wherein in the region a bundle of pipes through which fluid can flow is arranged and a housing encloses the pipe bundle and a movable working medium in a sealing manner, wherein a supporting structure forms a mechanical support of a wall of the housing against the action of an external pressure.

The invention relates to a module for a heat pump in accordance with thepreamble of claim 1.

WO 2010/112433 A2 describes a heat pump which has stacks of hollowelements in each of which an adsorption/desorption zone and acondensation/evaporation zone are arranged. The hollow elements are eachfilled with a working medium, which can be moved between the tworegions. An adsorbent is applied to metal sheets, which have rim holesfor the passage of tubes.

It is the object of the invention to specify a module for a heat pumpwhich has a pressure resistant, in particular vacuum resistant,structure.

According to the invention, this object is achieved for a modulementioned at the outset by means of the characterizing features of claim1. The provision of a supporting structure makes it possible by simplemeans to achieve improved pressure resistance of the housing, inparticular to a relatively high external pressure.

A plurality of such modules can be combined to form a heat pumpaccording to the invention, e.g. in accordance with the teaching of WO2010/112433 A2.

In general, a reduced pressure relative to the surroundings prevails insuch a module, at least under certain operating conditions, and thismakes particular demands on the design of the housing. By means of thesupporting structure, the externally acting pressure forces can beaccepted and/or distributed in an effective manner.

A supporting structure of this kind can be formed as a trapezoidalsheet, for example, comprising longitudinal seams aligned transverselyto longitudinal beads provided in a housing cover. In another embodimentin accordance with FIGS. 16 to 18, the trapezoidal sheet is dispensedwith and replaced by two supporting elements, which support two housinghalf shells provided with transverse beads relative to one another.Alternative detail configurations of the supporting structure arepossible, e.g. as a grid, a plurality of rods and the like.

In a preferred embodiment of the module, it comprises adsorberstructures in the first region (adsorption/desorption zone), comprisingat least one tube, through which a heat transfer fluid can flow, and anadsorbent, wherein the working medium can be adsorbed and desorbed onthe adsorbent, and the adsorbent is thermally connected to the tube,wherein the adsorbent is designed as at least one shaped body, inparticular a plurality of shaped bodies, which directly adjoins a tubewall of one of the tubes.

By means of the design of the adsorbent as a shaped body directlyadjoining the tube wall, direct heat transfer from the fluid to theshaped body through the tube wall is achieved. This can furthermoresimplify the structural design, save installation space and constructioncosts and increase effectiveness overall.

The concept of “directly adjoining” according to the invention should betaken to mean geometrically direct contact between the shaped bodies andthe shape of the tubes. Depending on the detail design, there can be oneor more further layers between a load bearing material of the tube wallsand the shaped bodies, e.g. adhesive, heat conducting paste, solderand/or an anticorrosion layer on the tube wall.

A preferred, but not essential, working medium for adsorption anddesorption is methanol. The adsorbent is advantageously based onactivated carbon.

In an advantageous embodiment, the shaped body has a thickness of atleast approximately 1 mm, preferably at least approximately 2 mm. Suchrelatively great thicknesses allow high effectiveness and optimizationof the installation space. In this context, an upper limit for thethicknesses of the shaped body structures is advantageously about 10 mmand, particularly preferably, about 6 mm.

One possible embodiment of the invention envisages that the shaped bodyis connected to the tube wall by means of a preferably flexible adhesivelayer. As a particularly preferred option, the adhesive layer issilicone-based, thereby achieving good flexibility with high heatresistance and chemical resistance at the same time. An example of apreferred adhesive based on silicone is ELASTOSIL® E43 or, as aparticularly preferred option, 1K addition-cured Semicosil 988.

As a preferred but not essential option, the adhesive layer furthermorehas additives to increase thermal conductivity. These can be boronnitride and/or finely ground graphite, expanded graphite and/or soot,for example. Metallic or ceramic particles are also possible.

The adhesive layer preferably has at least short-term temperaturestability of about 250° C., thus allowing at least one-time completedesorption of the adsorber, in the course of initial installation forexample. The adhesive layer has long-term resistance to the workingmedium, in particular methanol, up to at least about 130° C.

The adhesive layer is preferably chosen so as to have an elongation attear or elongation at break of at least about 200%, preferably about300%. Separation of the shaped bodies from the tube wall due todifferential thermal expansion with relatively large temperature changesis thereby avoided.

In another embodiment of the invention, provision is made to reduce thethermomechanical stresses which arise in thermal cycling by means ofpredetermined breaking points introduced into the shaped adsorberbodies. As a result, it is even possible to use less flexible types ofadhesive and/or very thin adhesive layers, which can compensate onlyrelatively small differences in thermal expansion. It is, of course,also possible to bring about the breaks before a module begins tooperate. In addition to the direct mitigation of thermomechanicalstresses, this opens up further diffusion paths for the working mediuminto and out of the adsorbent (see below).

In another possible embodiment of the invention, it is envisaged that atleast one of a plurality of shaped bodies rests against the tube wall ofthe tube under the action of a force, in particular in frictionalengagement. In this case, there is no positive fixing or adhesivebonding, thus allowing for optimum compensation of differences inthermal expansion. Retention under the action of force leads to adefined, even more direct and therefore greater heat transfer.

In a preferred detail design, at least one of the two, namely the tubeor the shaped body, has a substantially wedge-shaped cross section,wherein, in particular, at least one of the two is held under the actionof a force in a wedging direction. Here, shallow wedge angles of a fewdegrees are preferably chosen.

In principle, an adsorber structure according to the invention cancomprise both shaped bodies that are held by material engagement andalso shaped bodies that are held by purely nonpositive engagement.

In a generally advantageous embodiment, the tube is designed as a flattube or box section tube, wherein the shaped body preferably adjoinsbroad sides of the flat or box section tube. Flat tubes are simple andeconomical to produce and have large areas for heat transfer. Inprinciple, any known design of flat tube can be considered for use, e.g.welded and/or soldered tubes, hydroformed tubes, tubes with a flangedbutt weld, snap over tubes and/or B-type tubes.

In another advantageous embodiment, the tube is designed substantiallyas a round tube or polygonal tube, wherein the tube is embedded in twoor more shaped bodies. Such a design allows substantially dense stackingin two directions in space, this being particularly conducive to theutilization of the installation space. In a preferred detail design, theshaped bodies in which the tube is embedded have a polygonal, inparticular hexagonal, external outline overall, thus making it possibleto achieve substantially geometrically dense stacking.

In a possible detail design, the shaped bodies are of substantiallyplate-shaped design, wherein they have in each case a plurality ofindentations for partially surrounding some of the tubes. In this way,good utilization of space can be achieved with a small number ofindividual parts.

In a generally advantageous way, the shaped body has a recess which atleast partially forms a steam duct for the adsorbent and/or apredetermined breaking point of the shaped body. Thus, effective supplyand discharge of the working medium through the ducts is provided, evenin the case of a spatially dense arrangement of adjoining shaped bodies.The alternative or supplementary function as a predetermined breakingpoint allows defined breaking, e.g. due to locally excessive thermalexpansion. At the same time, the mechanical and thermal integrity of theoverall structure, in particular the thermal contact between the tubeand the adsorbent, is maintained. Through the formation of definedcracks parallel to the direction of heat conduction, the access area ofthe working medium and the kinetics of mass transfer are improved.

In a generally advantageous way, the tube is composed substantially ofan iron-based alloy. Such alloys are particularly robust with respect tomany working media, especially methanol.

In a preferred detail design, the tube is composed of a ferriticstainless steel (low coefficient of thermal expansion), e.g. 1.4509,1.4512 etc. and/or a tinplated stainless steel. It can also be composedof a standard tinplated steel, e.g. of low-cost tinplate. Anothervariant is to use galvanized base material, in particular galvanizedsteel. It is also possible to use low-alloy steel or stainless steel,e.g. DC03, if contact corrosion and surface corrosion can be avoided(the latter by means of suitable corrosion inhibitors in the fluid).

In the case of design as flat tubes, the hydraulic diameter ispreferably less than about 5 mm, preferably in a range between 1 mm and2 mm.

The wall thicknesses of the flat tube are advantageously in a range offrom 0.1 mm to 1 mm, preferably between 0.2 and 0.4 mm.

In the case of design as a round tube, said tube preferably has adiameter in a range between 4 mm and 6 mm. The round tube advantageouslyhas wall thicknesses in a range between 0.05 mm and 0.5 mm andpreferably between 0.1 mm and 0.3 mm. The round tube can be fitted withturbulence inserts for increasing the internal heat transfercoefficient.

In a particularly preferred embodiment of the module, the adsorberstructures are designed as a mechanical support for the housing, leadingto particularly high strength in respect of an external pressure. At thesame time, a spatially particularly dense arrangement of the shapedbodies and tubes is achieved here.

The housing wall of the module is preferably composed of an iron-basedalloy, e.g. steel, stainless steel, tinplated or galvanized steel or thelike. In particular, the material can correspond to a material of thetubes. In the case of embodiments in steel, the housing can be paintedon the outside or coated in some other way in order to preventcorrosion.

In a preferred detail design, there is in the evaporation/condensationregion no support for the housing by the inner tubes and structuresconnected thereto for the accumulation and release of the workingmedium. Since this region is generally narrower than the adsorptionregion, this region can be bridged in a cantilevered manner by thehousing with beaded- and/or trapezoidal sheet structures, and thereforeneeds no support on the sensitive inner evaporation/condensationstructures present in this region. As a particularly preferred option, asupporting frame can be provided between the two regions in the interiorof the housing in order to prevent excessive sagging of the housing inthis region.

In a preferred module, the adsorption/desorption region occupies alarger proportion of the module than the evaporation/condensationregion. As a particularly preferred option, the ratio of the volumestaken up by each of these regions within the housing is between about1.5 or 1.7 and about 4.

If the module does not have a condensation/evaporation region, use as anadsorptive heat and/or cold reservoir or in a conventional adsorptionheat pump concept comprising a plurality of adsorption reactors, with acommon or separate condenser and evaporator, can be envisaged, forexample.

A shaped body according to the invention having an adsorbent for a heatpump consists of a mixture comprising an adsorbent and a binder, whichcomprises a ceramic binder. The ceramic binder is based on a silicate,preferably but not necessarily on an aluminum silicate. Siliceousceramics, e.g. magnesium silicates (e.g. steatite) and magnesiumaluminum silicates (e.g. cordierite), are also possible.

The proportion of the ceramic binder by weight in the shaped body isbetween 5% and 50%, particularly preferably between 15% and 30%.

It is advantageous if the mixture contains a powder consisting of asorption-active base material with a particle size in a range between 2μm and 500 μm, preferably between 5 μm and 100 μm. The sorption-activebase material can be activated carbon, for example.

The mixture can contain additives to improve heat conduction, e.g.expanded graphite and/or boron nitride and/or silicon carbide and/oraluminum nitride. The additives preferably account for between 5% and50%, particularly preferably between 10% and 35%, of the mass.

As an alternative or supplementary measure, inorganic fibers can beadded, improving thermal conductivity and/or mechanical stability.

In a preferred embodiment, activated carbon fibers can be added, andthese can advantageously both include a heat conducting function and/ormechanical stabilization and perform an adsorption function.

A production method for the shaped body according to the invention cancomprise extrusion and/or sintering, for example. Sintering can takeplace under inert gas.

Further advantages and features of the invention will emerge from theillustrative embodiments described below and from the dependent claims.

In the text which follows, a number of preferred illustrativeembodiments of the invention are described and explained by means of theattached drawings.

FIG. 1 shows a three-dimensional opened-up view of a module havingadsorber structures according to the invention.

FIG. 2 shows the module from FIG. 1 in an exploded view.

FIG. 3 shows an exploded view of housing parts of the module from FIG.1.

FIG. 4 shows a schematic sectional view through the module from FIG. 1.

FIG. 5 shows a three-dimensional view of a first illustrative embodimentof an adsorber structure of the invention with retention by materialengagement.

FIG. 6 shows a sectioned view through a stack arrangement of a pluralityof adsorber structures from FIG. 5.

FIG. 7 shows a three-dimensional view of adsorber structures from FIG.5, stacked in two directions in space.

FIG. 8 shows section views of a number of designs of flat tubes of theadsorber structures from FIG. 5 to FIG. 7 and a section view of a flattube inserted in a tube sheet.

FIG. 9 shows a schematic sectioned view of another embodiment ofadsorber structures with nonpositive retention.

FIG. 10 shows a modification of the embodiment from FIG. 9 havingwedge-shaped flat tubes.

FIG. 11 shows a three-dimensional view of another example of an adsorberstructure of the invention having a round tube.

FIG. 12 shows stacking of adsorber structures according to FIG. 11 intwo directions in space.

FIG. 13 shows a plate-shaped shaped body of another embodiment of anadsorber structure.

FIG. 14 shows a modification of the shaped body from FIG. 13.

FIG. 15 shows an adsorber structure having round tubes and shaped bodiesaccording to FIG. 13 and FIG. 14.

FIG. 16 shows an exploded drawing of the parts of an alternative housingconcept

FIG. 17 shows a modular construction having two supporting elements incross section

FIG. 18 shows the modular assembly having two supporting elementswithout the upper housing half shell

FIG. 19 shows another alternative housing concept having a one-piecehydroformed housing

FIG. 20 shows the internal construction of the one-piece hydroformedhousing concept having a supporting element

FIG. 21 shows the hydroformed housing concept (internal view withsupporting frame and flat tubes)

The module shown in FIG. 1 is one of several combined modules of a heatpump. It comprises a housing 1, in which a first region as anadsorption/desorption region 2 and a second region as acondensation/evaporation region 3 are arranged adjacent to one another.Each of the regions 2, 3 comprises a plurality of tubes 4, in thepresent case flat tubes, which are arranged as a bundle stacked in twodirections in space.

Here, the tubes 4 of the first region are each designed as an adsorberstructure 5 (see FIG. 5). In this case, the broad sides of the flattubes 4 are each connected over an extended area to a shaped body 6, inthe present case by adhesive bonding. The shaped body 6 is composed of amixture of adsorbent, in the present case activated carbon, and binder.

An adhesive layer 7 for connecting the shaped bodies 6 to the tubes 4comprises a flexible adhesive based on silicone, in the present caseSemicosil 988.

Recesses 6 a, 6 b are formed in the shaped bodies, serving as steamducts 6 a for the joint supply and discharge of working medium and/or aspredetermined breaking points 6 b, by means of which separation of theshaped bodies from the tube 4 under excessive thermal stress is avoided.

The tubes 4 project beyond the shaped bodies 6 in end regions 4 a andopen into rim holes 10 a in tube sheets 10. The latter are embodied insuch a way that they can flexibly accommodate thermomechanicaldifferences in expansion between the housing parts, on the one hand, andthe tubes, on the other hand. For this purpose, the tubes can also haveone or more annular beads surrounding the rim hole region of the tubebundles.

The flat tubes 4 can be of any desired design, being designed as alongitudinally laser-welded tube, snap over tube, B-type tube or flangedtube according to FIG. 8 for example (from left to right).

FIG. 9 and FIG. 10 show embodiments having flat tubes 4, in which theshaped bodies 6 are not attached by adhesive bonding or materialengagement but nonpositively, in the present case by frictionalengagement.

In the example shown in FIG. 9, the shaped bodies are of slightlywedge-shaped design, and the flat tubes are of conventional design. Eachshaped body 6 extends across a plurality of flat tubes 4 in a depthdirection. In the longitudinal direction or stacking direction, theshaped bodies 6 alternate in orientation.

In the example shown in FIG. 10, both the shaped bodies 6 and the flattubes 4 are slightly wedge-shaped. In this modification, each shapedbody extends over one flat tube, with flat tube rows situated one behindthe other in the depth direction being shown in reverse orientation. Asa preferred option (not shown in FIG. 10), the shaped bodies projectbeyond the flat tubes in the depth direction, as also in FIG. 9, andtherefore the shaped bodies are held in the wedging direction by supportmeans or means subjected to an elastic force (not shown). Respectiveholding elements 8 are provided at each end in the stacking direction,said holding elements supporting at least the end-mounted shaped bodiesunder a static or elastic force in this direction. At least part of thesupporting force in the stacking direction can also be taken by thetubes 4 accommodated in rim holes. As a further detail, the end-mountedsupport means for the tube bundle can also be braced against oneanother, e.g. by means of one or more straps.

In the illustrative embodiment shown in FIG. 11, flat tubes are replacedby round tubes 4, which can also be of polygonal design, depending onthe particular modification.

The round tubes 4 are each surrounded partially by a plurality of shapedbodies 6, in the present case two shaped bodies. Overall, the tube 4 iscompletely embedded in the shaped bodies 6 (apart from tolerance oradhesive bonding gaps), and overall they have a hexagonal externaloutline in the present case. As a result, the adsorber structures 5,each consisting of one tube 4 and two shaped bodies 6, can be stackeddensely in two directions in space (see FIG. 12).

The preferred thickness of the shaped bodies 6 is obtained from theaverage length of the heat conduction path, for which the samespecifications apply in the case of all the shapes (preferably between 1mm and 10 mm, particularly preferably between 2 mm and 6 mm).

As is apparent, the edges of the external outline of the shaped bodieshave a defined rounding, and therefore respective steam ducts 6 a areformed in the stack.

Additional steam ducts extending transversely to the longitudinal axisof the tubes can be formed by segmenting the shaped bodies in thelongitudinal direction of the tubes and spacing the segments apart (notshown).

Depending on the requirements, the example shown in FIG. 11 and FIG. 12can be designed with material and/or nonpositive attachment of theshaped bodies 6 to the tubes 4. With respect to the preferred materialattachment, the same adhesive system can be used as that in the otherillustrative embodiments.

In the example shown in FIG. 13 to FIG. 15, the shaped bodies 6 are ofsubstantially plate-shaped design, wherein each of the plates 6 has aplurality of indentations 9 for partially surrounding the tubes 4. Inthe present case, the tubes are round tubes, although this is notessential.

The shaped bodies 6 each have recesses 6 a, 6 b to form steam ducts andpredetermined breaking points. It is self-evident that a recess 6 a, 6 bcan also perform both functions simultaneously. They are preferablyformed and arranged either in the neutral plane of the heat flux and/oras narrow gaps in the direction of heat flux.

FIG. 15 shows an adsorber structure 5 which comprises a stack of aplurality of the shaped bodies shown in FIG. 3 and FIG. 4 with rows ofround tubes 4 arranged in between.

In general, the adsorber structures described above preferably have thefollowing properties:

The tubes of the bundles are connected to the shaped bodies in a mannerwhich allows good heat conduction, with overlaps of the ends being from5 mm to 15 mm.

The tubes of the tube bundles are characterized by:

the base material being an iron-based material, particularly preferablyferritic stainless steel; this has a lower coefficient of thermalexpansion than austenitic stainless steels.

As an alternative, tinplated stainless steel or tinplated steel(tinplate) can be used as a raw material—depending on the joining methodchosen. Another variant is to use galvanized base material, inparticular galvanized steel. Using noncorrosive working media on theinside of the module, such as methanol and heat transfer mediacontaining corrosion inhibitors, also makes it possible to useinexpensive steels (structural steel). Moreover, said steels can also beadditionally provided with corrosion protection on the outside bycoating or painting only after the final material joining of the overallmodule.

The flat tubes 4 (FIG. 5 to FIG. 10) have a hydraulic diameter of <5 mm,preferably in a range between 1 and 2 mm. The wall thicknesses of theflat tubes are in a range of from 0.1 to 1 mm, preferably between 0.2 mmand 0.4 mm.

The round tubes (FIG. 11 to FIG. 15) preferably have a diameter in arange between 4 and 6 mm. The round tubes 4 have wall thicknesses in arange between 0.05 mm and 0.5 mm, preferably between 0.1 mm and 0.3 mm.

In particular, the shaped bodies of the illustrative embodimentsdescribed above preferably have features in accordance with thefollowing examples or are preferably produced in the following manner:

EXAMPLE 1

1. Use of a highly porous adsorbent in powder form as anadsorption-active base material for adsorbing the selected workingmedium (in the present case methanol), having the following properties:

1.1. Preferably having an adsorption isotherm of type 1.

2. Adsorber compound consisting of:

2.1. Powder of the sorption-active base material with a particle size ina range between 2 μm and 500 μm, preferably between 5 μm and 100 μm.

2.2. Ceramic binder based on siliceous ceramics such as magnesiumsilicates (e.g. steatite), magnesium aluminum silicates (e.g.cordierite) and aluminum silicates (e.g. stoneware, porcelain). Thepercentage by weight of the ceramic binder in the shaped body is between5% and 50%, particularly preferably between 15% and 30%.

2.3. Heat-conducting additives, especially expanded graphite, BN, SiC,AIN, the percentage by mass being between 5% and 50%, preferably 10% to35%.

2.4. Optionally inorganic fibers for reinforcement and increasingthermal conductivity.

2.5. Optionally activated carbon fibers, which both have sorptiveproperties and can perform a heat conducting function.

3. Shaped bodies produced from adsorber compound by the followingmethod:

Version 1:

3.1. Production of a plastic composition consisting of the componentslisted in 1., 2. above, plus water and a plasticizer.

3.2. Extrusion, e.g. to give a film or a strand which is rolled to givea film, into which channels, grooves or blind holes are rolled, followedby cutting.

3.3. Alternatively, extrusion to give a film with the profile alreadyprovided, having channels or grooves to improve mass transfer, followedby cutting into strips.

3.4. Drying according to requirements, with measures to maintain theshape.

3.5. Sintering in an inert gas atmosphere at a temperature and for adwell time that are required for the hardening or sintering of thealuminum silicate binder to give a stable matrix.

Version 2:

Production of granules consisting of the components listed above and ofan additive (e.g. a wax), which performs the function of a green binderafter a pressing operation. One example of such a production process isthe production of spray granules.

3.6. Introduction of the granules into a mold and pressing to give theshape of the adsorber structure.

3.7. Sintering in an inert gas atmosphere at a temperature and for adwell time that are required for the hardening or sintering of thealuminum silicate binder to give a stable matrix.

3.8. To establish a particular porosity and a defined pore structure, apore former, e.g. in the form of powdered polymers or in the form oforganic fibers, can optionally be added to the starting mixture.

The following features are preferably provided for the geometricalconfiguration of the shaped bodies:

A plate shape with a thickness in a range between 1 mm and 10 mm,preferably in a range between 2 and 6 mm.

A channel structure on one or both sides with a channel spacing thatcorrelates with the plate thickness by a factor of between 0.5 and 2. Achannel width is <1 mm, preferably <0.5 mm.

A channel depth which correlates with the plate thickness by a factor ofbetween 0.2 and 0.8.

The following features are preferably present in respect of the adhesivelayer 7 for attaching the shaped bodies 6 to tubes 4:

flexible adhesive layer characterized by:

-   -   full-surface wetting of the contact surface between the        adsorption body and the metal support;    -   optional partial usage of the channel volume as an adhesive        displacement volume for achieving thin adhesive layers;    -   temperature stability up to 250° C. for the purpose of adsorber        desorption before installation;    -   long-term stability relative to the working medium, preferably        methanol, up to 130° C.;    -   enrichment with heat conduction additives such as BN, finely        ground graphite, expanded graphite or soot, depending on        requirements;    -   elongation at tear (elongation at break) at room temperature is        at least 300%

a layer thickness of the adhesive layer is between 10 μm and 500 μm,preferably between 50 μm and 150 μm.

The heat transfer fluid flowing through the tubes 4 is a matter of freechoice, but is preferably a water/propylene glycol mixture.

The heat pump module shown in FIG. 1 to FIG. 4 preferably but notnecessarily has, in a first region 2 thereof, adsorber structures inaccordance with one of the illustrative embodiments described above. Anydesired evaporation/condensation structures can be arranged in thesecond region 3, but preferably structures in accordance with EP 1 918668 B1.

The housing 1 of the module comprises a lower housing part 1 a and anupper housing part 1 b, which each have stamped longitudinal beads in afirst direction (direction of through flow) for reinforcement.

The housing 1 furthermore comprises the sheets 10 with the rim holes 10a, into which the tubes 4 are inserted. The edges of the sheets aresurrounded in a hermetically sealed manner by the two housing parts 1 a,1 b.

Respective supporting structures 11 are provided between housing parts 1a, 1 b and the first and second regions 2, 3. The supporting structures11 are of extended-area design, being designed in the present case astrapezoidal sheets (see, in particular, FIG. 2 and FIG. 3). Folds in thetrapezoidal sheets 11 are oriented perpendicularly to the longitudinalbeads of the housing parts 1 a, 1 b. The trapezoidal sheets rest on theinside of the housing parts 1 a, 1 b and are securely connected theretoby means of material joining methods, e.g. resistance spot welding.

Overall, the crisscrossing of the longitudinal beads and of the foldsresults in a high pressure stability of the housing walls, especially inrespect of external excess pressure and good thermal decoupling betweenthe internal structures and the housing parts.

The stacked adsorber structures 5 in the first region represent afurther support. At least at operating temperatures and/or under acorresponding pressure effect (assembly with the minimum clearancenecessary), the shaped bodies 6 rest perpendicularly one upon the otherand on the trapezoidal sheets of the housing, resulting in optimumsupport with respect to the generally relatively high external pressure.

The sheets 10 are provided from the outside with plastic header tanks 12of the kind which are known in principle from the construction of heatexchangers. The header tanks 12 have connections 12 a for supplying anddischarging heat transfer fluid.

Connections 13 for filling the module with working medium, in thepresent case methanol, are provided in the sheets 10. In theillustration in FIG. 4, one connection 14 is designed as a pressurerelief valve with a valve plunger that can be actuated. Increasedoperating reliability and/or multiple filling of the module can therebybe achieved.

A supporting frame 15 is arranged in the module between the first region2 and the second region 3 in order to further improve mechanicalstability, especially in the vicinity of the second region 3. Ingeneral, in contrast to the adsorber structures 5 of the first region 2,no provision is made for the active structures for evaporation andcondensation of the second region to rest upon one another in the mannerof a mechanical support. This prevents condensed working medium fromflowing down from the top between the structures.

Another particularly preferred further embodiment has the followingdiffering features in accordance with FIGS. B1 to B3:

The direction of the housing beads of the two half shells is rotatedthrough 90° and divided into three segments, between which there areundeformed flat housing surfaces.

In the region of the undeformed flat surfaces, the housing shells aresupported internally by a total of two supporting frames, which havetabs which pass partially through the housing shells. These tabs arewelded materially and in a hermetically sealed manner to the housingparts afterwards from the outside, the advantage being that thisembodiment can absorb even relatively high excess pressures withoutdamage.

The embodiment shown by way of example, having two supporting frames, incombination with the modified structure of the housing half shells,makes it possible to eliminate the trapezoidal sheets and hence toreduce the internal surface area and the mass of the housing.

The following features preferably apply to the construction of themodule and, specifically, to the housing 1:

Both tube bundles of regions 2, 3 open at the ends into the tube sheets10 and are connected materially thereto. The tube sheets have thefollowing features:

A metal base material with low heat conduction, preferably austeniticstainless steel, such as 1.4301 or 1.4404. A thickness range of the tubesheet is between 0.3 mm and 1.5 mm, preferably between 0.5 and 1 mm.Depending on the tube production method and joining method used,tinplated or galvanized base materials or uncoated inexpensive steelscan also be used.

Spacing of the tube sheet leadthroughs for thermal decoupling of the tworegions 2, 3 in accordance with the thermal conductivity of the tubesheets is provided (adiabatic zone 16). As an alternative, however, thetube sheet can also be provided with a stamped transverse bead to reduceheat conduction losses between the regions.

The tube sheets 10 have integrally formed tube rim holes 10 a and havean optional coating, which is matched to the type of tube used and tothe fluidtight joining method implemented, e.g. a layer of tin in thecase of joining by means of soft soldering.

A fluidtight tube/sheet connection can be produced by remote laserwelding, characterized by:

-   -   punching and push-through formation of a collar of the same        height (FIG. 8);    -   use of a longitudinally laser welded tube (FIG. 8);    -   flanged butt welds at the ends in the heat conduction region.

As an alternative or supplementary measure, a fluidtight tube/sheetconnection can be achieved by soft soldering, characterized by:

-   -   use of one of the tubes illustrated in FIG. 8, preferably        however a B-type tube, snap over tube, flanged tube or round        tube;    -   gap widths between 0 mm and 0.5 mm;    -   use of either uncoated base materials and use of flux or use of        coated base materials and omission of flux;    -   in the case of the version involving uncoated base materials and        the use of flux, steels that are not Ti-stabilized (Ti content        only within the range of customary impurities) or, in        particular, stainless steels should be used.    -   joining by dip soldering, flow soldering, radiation soldering,        hot gas soldering, inductive and/or furnace soldering of base        materials precoated with solder. As an option, additional solder        can be supplied in the form of solder foil, solder paste, solder        wire and the like in accordance with the prior art for the        purpose of gap filling.

As an alternative or supplementary measure, a fluidtight tube/sheetconnection can be achieved by adhesive bonding, characterized by:

-   -   use of flat tubes (FIG. 8), wedge-shaped flat tubes (FIG. 10) or        round tubes (FIGS. 11 to 15);    -   use of a suitable adhesive, preferably from the group comprising        epoxy resin adhesives;    -   bonding gap <0.2 mm.

The housing 1 of the hollow element is preferably characterized by:

-   -   base material consisting of stainless steel, preferably        austenitic;    -   shell-type construction comprising two housing parts 1 a, 1 b        having;    -   longitudinal beads in the direction of the longitudinal axes of        the tubes, running out toward the rim;    -   flat rim for material, fluidtight connection to the tube sheets        10 by flanged butt welding, soft soldering and/or adhesive        bonding;    -   U-shaped seam on one of the longitudinal edges in each case        (longitudinal edge reinforcement and splash guard during        optional laser welding);

As a particularly preferred option, there is a reinforcement by atrapezoidal sheet 11 with a seam edge direction perpendicular to theexternal beading, characterized by:

-   -   trapezium height adjusted for support of the inner trapezium        surfaces on the adsorber structure;    -   recesses for 90°-forming toward the side faces;    -   spot welding to the outer shells;    -   the housing half shells 1 a, 1 b are preferably connected to one        another materially and hermetically by through-welding the upper        and lower sheet by means of deep penetration laser welding,    -   the sheet/housing connection is made by flanged butt welding;    -   optional additional sealing is effected by means of a sealing        adhesive in the bonding gap 17 (FIG. 4).    -   As an alternative to the fluidtight connection of parts by means        of welding technologies, soft soldering and/or adhesive bonding        can be used.

The supporting frame 15 is arranged in the region of the adiabatic zone16 between the sorption zone 2 and the phase change zone 3 and ispreferably characterized by:

-   -   frame with bars angled in a U or L shape;    -   frame height matched to the clear width between the inner        surfaces of the trapezoidal sheet.

The connections 13, 14 for evacuation and filling preferably comprisestainless steel or copper stubs which are welded into the tube sheet bymeans of resistance welding and into which respective evacuation andfilling tubes made of copper are soldered for pinching off, ultrasonicwelding and/or soldering shut.

As an alternative, they can be stainless steel fittings which arescrewed into the stubs and sealed off by means of metal gaskets and intowhich an evacuation/filling tube made of copper is soldered for pinchingoff and soldering shut or ultrasonic welding.

The header tanks 12 preferably comprise an injection molded plasticinner part substantially resistant to hydrolysis, preferably PA or PPS,having:

-   -   an elastomer seal for sealing off with respect to the tube        sheet;    -   respective fluid connections;    -   respective vent stubs;

An optional contact pressure bell made of metal (not shown) can have:

-   -   bell depth adjusted to provide support for the internal sealing        plastic inner part;    -   guides and supporting elements for straps;    -   straps for pressing two opposite header tanks in each case        against the tube sheets of the tube bundles for the sorption        zone 2 and phase change zone 3;    -   clamping bars with clamping screws for pressing two opposite        header tanks on in each case.

FIGS. 16 to 18 show a module consisting of a plurality of combinedmodules of a heat pump. It comprises a housing 1 consisting of the upperhousing half 1 b and the lower housing half 1 a, in which a first regionas an adsorption/desorption region 2 and a second region as acondensation/evaporation region 3 are arranged adjacent to one another.In this case, the adsorption/desorption region 2 is divided into twosubmodules, which are divided by a supporting element 15. Each of theregions 2, 3 comprises a plurality of tubes 4, in the present case flattubes, which are arranged as a bundle stacked in two directions inspace.

In this case, the tubes 4 of the first region are each designed as anadsorber structure 5. Here, the broad sides of the flat tubes 4 are eachconnected to a shaped body 6 over an extended area, in particular by anadhesive bond for example. The shaped body 6 is composed of a mixture ofadsorbent, in the present case activated carbon, and binder.

Recesses 6 a, 6 b are formed in the shaped bodies, serving as steamducts 6 a for the joint supply and discharge of working medium and/or aspredetermined breaking points 6 b, by means of which separation of theshaped bodies from the tube 4 under excessive thermal stress is avoided.

The tubes 4 project beyond the shaped bodies 6 in end regions 4 a andopen into rim holes 10 a in tube sheets 10. The latter are embodied insuch a way that they can flexibly accommodate thermomechanicaldifferences in expansion between the housing parts, on the one hand, andthe tubes, on the other hand. For this purpose, the tubes can also haveone or more annular beads surrounding the rim hole region of the tubebundles.

The two supporting elements 15 are arranged parallel to the longitudinalextent of the tubes 4, which support two housing half shells 1 a, 1 bprovided with transverse beads on one another. Alternative detaildesigns of the supporting structure are possible, e.g. as a grid, aplurality of rods and the like.

In another embodiment of the invention, in accordance with FIGS. 19 to21, the housing consists of at least one housing region 100 in the formof a cylinder segment and of a second, smaller housing region 101 of anydesired shape, which preferably forms a single hydroformed component.Here, the cylinder segment 100 preferably surrounds the larger sorptionzone (adsorption/desorption zone) of the module in such a way that theregion of transition to the second housing region 101 comes to lie inthe adiabatic zone. In the present case, this region of transition issupported by a supporting frame 102 for absorbing the differentialpressure forces between the interior and the exterior. Both housingregions 100, 101 are provided with beads 103 for shape stabilization.This supporting element 102 is preferably designed in such a way that itis connected materially, e.g. by welding, to the hydroformed housing inorder to be able to absorb even differential pressure forces acting fromthe inside outward.

1. A module for a heat pump, comprising an adsorption/desorption region,wherein in the region a bundle of tubes through which fluid can flow isarranged and a housing encloses the tube bundle and a movable workingmedium in a sealing manner, wherein a supporting structure forms amechanical support for a wall of the housing against the action of anexternal pressure.
 2. The module as claimed in claim 1, wherein acondensation/evaporation region is furthermore provided in the module,in which region a bundle of tubes through which fluid can flow isarranged, wherein the working medium can be moved between theadsorption/desorption region and the condensation/evaporation region. 3.The module as claimed in claim 1, characterized by an adsorber structurecomprising at least one tube, through which a heat transfer fluid canflow, and an adsorbent, wherein a working medium can be adsorbed anddesorbed on the adsorbent, and the adsorbent is thermally connected tothe tube, wherein the adsorbent is designed as at least one shaped body,in particular a plurality of shaped bodies, which directly adjoins atube wall of one of the tubes.
 4. The module as claimed in claim 3,wherein the shaped body forms a mechanical support for a wall of thehousing against the action of an external pressure.
 5. The module asclaimed in claim 3, wherein at least one of the plurality of shapedbodies rests against the tube wall of the tube under the action of aforce, in particular in frictional engagement.
 6. The module as claimedin claim 5, wherein at least one of the two, namely the tube or theshaped body, has a substantially wedge-shaped cross section, wherein, inparticular, at least one of the two is held under the action of a forcein a wedging direction.
 7. The module as claimed in claim 3, wherein thetube is designed as a flat tube, wherein, in particular, the shaped bodyadjoins a broad side of the flat tube.
 8. The module as claimed in claim3, wherein the tube is designed substantially as a round tube orpolygonal tube, wherein the tube is embedded in two or more shapedbodies.
 9. The module as claimed in claim 3, wherein the flat tubes arecomposed of an iron-based alloy, in particular a ferritic iron-basedalloy, which is coated, in particular for the purpose of joining and/orof corrosion resistance.
 10. The module as claimed in claim 9, whereinthe shaped bodies in which the tube is embedded have a polygonal, inparticular hexagonal, external outline overall.
 11. The module asclaimed in claim 9, wherein the shaped body is of substantiallyplate-shaped design, wherein it has in each case a plurality ofindentations for partially surrounding some of the tubes.
 12. The moduleas claimed in claim 10, wherein the shaped bodies are adhesively bondedto the tubes by means of a thermoplastic adhesive, e.g. a silicone-basedadhesive.
 13. The module as claimed in claim 12, wherein the adhesivehas a low density of uncrosslinked molecules.
 14. The module as claimedin claim 1, wherein the housing wall of the module is composed of aniron-based alloy, in particular steel, stainless steel, tinplated steelor galvanized steel, wherein the housing wall is painted, in particularon the outside.
 15. The module as claimed in claim 1, wherein noTi-stabilized steels and/or stainless steels are used in assembling thetube/sheet and the sheet/housing joint by means of soft soldering. 16.The module as claimed in claim 1, wherein there is in theevaporation/condensation region no support by the inner tubes andstructures connected thereto for the accumulation and release of theworking medium.
 17. The module as claimed in claim 1, wherein theadsorption/desorption region occupies a larger proportion of the modulethan the evaporation/condensation region, wherein, in particular, theratio of the volumes taken up by each of these regions within thehousing is between about 2 and about
 4. 18. The module as claimed inclaim 1, wherein the housing is embodied as a single-shell housingformed by hydroforming.